Sequestration of Pb(II), Ni(II) and Zn(II) biosorption onto brown seaweed Sargassum wightii: Isotherm and kinetic modeling

This analysis is aimed at exploring the potential of brown seaweed Sargassum wigtii for the sequestration of lead, nickel, and zinc metal ions from aqueous solutions. The biosorption process was identified by FTIR and SEM analytics on the contact between positive metal ions and negatively-charged functional groups on S. wightii's surface. Biosorption isotherms obtained at pH 5, 4, and 8 for Pb(ii), Ni(ii), and Zn(ii) indicate that the seaweed provides a greater intake of Pb (86.37 mg/g), with Zn (70.16 mg/g) and Ni (56.74 mg/g). The above-mentioned pH mechanism significantly affected the biosorption capacity of brown algae. Such varying affinity was measured by atomic weight, the radius of metal ions, and the negative charges of electrons of the biosorbent for the three metal ions. The Toth model improved projected experimental isotherm results with strong correlation coefficients (R-2) from different isotherm models (Langmuir, Freundlich, Toth, and Sips). Kinetic tests found very strong metal removal efficiency by S. wightii, with 99% being completed in 90 min. Desorption tests with different elutant components (0.01 M NaOH, HCl, and EDTA) revealed that 0.01 M HCl could accomplish the highest desorption of all metal ions from metal-loaded S. wightii.